So it tried to submit my beatmapset when this error appeared. I tried to use the fix from the "Resolved Issues" place but still no luck

Notably, Single 24's .osu file's BeatmapSetID always changes to that number (even though i've set it to -1) right when i pressed "Upload Beatmap" from the editor. This doesn't happen to the .osu files for other difficulties

First, Copy the map folder (located in /songs/) to somewhere else (this is to have a backup just incase)

One done, go into osu! and delete the map. Once osu! has deleted the map, download this https://eat.s-ul.eu/vyW45iEN.osz and import it into osu! Immediately after importing, go into the editor and attempt to submit it.